A green discoloration is classic for Pseudomonas bacterial infection. The infection turns from green to brown to black depending on how long it has been active. If the infection is between the nail bed and the nail plate, you will need to see your dermatologist. If it is on the nail plate surface under an acrylic overlay, you can take off the overlay and expose it to the air and apply alcohol twice daily to keep it dried out. The stain will remain and will grow out with the nail plate.

If it is under the nail plate and the nail plate is separating from the nail bed, you will need oral antibiotics to kill the infection.

I have painful throbbing finger tip, i've had this for a few days already. there is some yellow/green stuff just next to my nail in my left middle finger looks like puss, i didn't hurt my finger in anyway, i just felt it becoming painfull and my finger tip got swollen and very hot, how can i treat this?

Pseudomonas is not that hard to 'kill' - you only need to keep the nail plate dried out as well as the area between the anil plate and the nail bed if it has separated. Apply a drop of alcohol to the area at least twice daily. Since Pseudomonas is a 'colored' infection, the stain (which is composed mainly of iron compounds) will remain and will have to grow out with the nail plate. Removing the source of the infections 'food' (moisture) will help to kill the bacteria. Keep the nail dried out for a few weeks and it should be fine.